ABSTRACT
Transient Eulerian simulations of multiphase flow inside a laboratory-scale circulating fluidized bed (CFB) riser were performed with air, bed material, and a secondary solid phase to evaluate the mixing of the secondary solid phase. This simulation data can be applied in model development or for computing terms that are commonly used when modeling mixing with simplified models (pseudo-steady state, non-convective models, etc.). The data was produced with transient Eulerian modeling using Ansys Fluent 19.2. The simulations were done with one fluidization velocity and bed material, while the density, particle size, and inlet velocity of the secondary solid phase was varied and 10 simulations per each secondary solid phase case were simulated for 1 s, each simulation having different starting conditions (flow state of the air and bed material) inside the riser. These 10 cases were then averaged to provide an average mixing profile for each secondary solid phase. Both the averaged and un-average data are included. The details of the modeling, averaging, geometry, materials, and cases are described in the open-access publication by Nikku et al. (Chem. Eng. Sci. 269, 118503).
ABSTRACT
Hard-disk simulations are used for two-dimensional rapid granular shear flows of circular disks between two rotating cylinders. The intermittency effects associated with the rate of the energy dissipation of collisions are studied. The statistics of intermittent signals of energy dissipation reveals that a power law governs the dynamics of rapid shear granular flows. A dynamical system approach based on the Gledzer-Ohkitani-Yamada shell model of turbulence is employed to reproduce signals for energy dissipation that are statistically consistent with those from simulations. The results suggest that rapid granular flows can be analyzed by appropriate turbulent models.